Problem
When using Google Search grounding with Gemini API, the grounding metadata only returns Vertex AI Search redirect URLs (`https://vertexaisearch.cloud.google.com/grounding-api-redirect/…\`) instead of the actual source URLs.
## Current State
- `chunk.web.uri`: Returns redirect URL
- `chunk.web.title`: Only contains domain name (e.g., “aljazeera.com”)
- No field provides the complete original URL
Requested Feature
Add a field in grounding metadata that contains the actual source URL (e.g., `chunk.web.source_url` or `chunk.web.original_uri`).
Use Cases
- Programmatic URL validation and accessibility checks
- Proper citation generation with complete URLs
- URL-based caching and deduplication
- Source archival and compliance auditing
- Implementing URL allowlist/blocklist filtering
## Impact
Affects developers building citation systems, research tools, legal/compliance applications, and any system requiring actual source URL verification.